2c32c7ae1a
As described in the comments, sfdisk was rewritten for util-linux 2.26 (as shipped in F22) and now interprets arguments a sectors, rather than cylinders. The current partitioning line is "1 - - *" (start/size/type/bootable) which means you start getting: --- /usr/sbin/grub2-install: warning: this msdos-style partition label has no post-MBR gap; embedding won't be possible. /usr/sbin/grub2-install: warning: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discoura ged.. /usr/sbin/grub2-install: error: will not proceed with blocklists. --- when building images, because the start is interpreted by the new sfdisk as sector 1 and it crams the partition right next to the MBR. Specifying "-" for the size is undefined in the man page; even reading the source it's not totally clear what "-" for the size does [2]. In any case, the alignment is wrong in sectors or cylinders; we want to be a multiple of 4KiB for best performance. The intent here is to create one single, Linux, bootable, partition taking up the whole disk starting at 1MiB, so "2048 + L *" makes this clear. We use the -uS argument to ensure both versions treat this start-value as a sector offset (newer sfdisk essentially ignores the argument). As described in the comments, bugs in the older sfdisk necessitate usage of "--force". Although we could choose more or less, it seems most common to align to a 1MiB boundary (i.e. starting at sector 2048). libguestfs has some disucssion around --alignment and where it sets it's default to this [3]. The 2.26-era sfdisk also defaults to putting partitions here. 1MiB should be enough for GPT schemes in the future as well. [1] https://github.com/karelzak/util-linux/blob/master/libfdisk/src/script.c#L1050 [2] https://bugzilla.redhat.com/show_bug.cgi?id=1249893 [3] http://libguestfs.org/virt-resize.1.html Change-Id: I2c2966f98d1d5ad4ebb433ea148b3b26c65dc1b5 |
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| block-device.d | ||
| cleanup.d | ||
| finalise.d | ||
| README.rst | ||
== vm == Sets up a partitioned disk (rather than building just one filesystem with no partition table). By default the disk will have grub[2]-install run on it. In case GRUB2 is not available in the system, a fallback to Extlinux will happen. It's also possible to enforce the use of Extlinux by exporting a DIB_EXTLINUX variable to the environment.